Technical Field
Embodiments of the subject matter disclosed herein relate to controlling engine exhaust gas recirculation flow.
Discussion of Art
Engine systems may be configured to maintain emissions within regulated limits while providing optimal fuel economy. Ambient conditions may impact emissions, and thus engine systems may be configured to maintain emissions over a range of ambient conditions. For example, air flow through a turbocharger and heat rejection by an intercooler may each be impacted by ambient temperature and pressure. Changes in airflow may impact air-fuel ratio and intake manifold oxygen concentration, which in turn may impact particulate matter and NOx production. Likewise, changes in heat rejection from the intercooler may impact manifold air temperature, which in turn may impact NOx and particulate matter production.